1. Technical Field
The present invention relates to image display methods, devices, and projectors.
2. Related Art
Image display devices such as television receivers display images on a frame basis. Object images are animated by being displayed with a slight image displacement on a frame basis with a frame frequency of 60 Hz, for example. As such, the object is put in motion in the images.
In FIGS. 8 and 11, both (a) show display images of a moving object on a frame basis, and the vertical axis indicates time. In FIGS. 8 and 11, both (b) show how the display images look if a user's eyes follow the moving object.
FIG. 8 shows a case with an impulse-type image display device exemplified by a CRT or others. As shown in (a) in FIG. 8, with an impulse-type image display device, images of a moving object appear impulsively for every frame. This thus reduces, as shown in (b) in FIG. 8, a motion blur streak 70 observed to the image contour is reduced in width even if a user's eyes follow the moving object.
FIG. 9 shows a case with a hold-type image display device exemplified by a liquid crystal display or others. As shown in (a) in FIG. 9, with a hold-type image display device, images of a moving object are continuously displayed for every frame. With such image display, a contour position 72 of the moving object greatly changes at regular intervals. As a result, as shown in (b) in FIG. 9, when a user's eyes follow the moving object, the motion blur streak 70 observed to the image contour is increased in width.
In the natural world, the motion blur streak is reduced in width when a person follows a moving object with his or her eyes. In this sense, there has been a demand for the hold-type image display device such as liquid crystal display to achieve such visual characteristics as FIG. 8.
To meet such a demand, for example, Patent Document 1 (JP-A-2002-351382) is proposing a method for impulsive image display in a hold-type image display device as in an impulse-type image display device. Also proposed thereby is a method, for image display, of doubling a frame frequency of input image signals, and inserting generated image signals between any consecutive input image signals.
FIG. 10 shows a case with impulsive image display in a hold-type image display device. In such a case, as shown in (a) in FIG. 10, a black period is inserted to each of the image frames. As a result, as shown in (a) in FIG. 10, the motion blur streak 70 observed to the image contour is reduced in width for the moving object.
FIG. 11 shows a case with image display with generated image signals inserted between any consecutive input image signals. In this case, as shown in (a) in FIG. 1, used for insertion between any two input image signals are generated image signals intermediate for the consecutive input image signals. This accordingly reduces the change level of the contour position 72 of the moving object, and as shown in (b) in FIG. 1, the motion blur streak 70 observed to the image contour is reduced in width for the moving object.
The issue here is that such a method of impulsive image display in a hold-type image display device causes a problem of lowering the image intensity due to inserted black periods compared with any conventional hold-type image display devices.
The method of doubling a frame frequency of input image signals, and inserting generated image signals for image display causes another problem of increasing the signal processing load. This is because, for such a method, there needs to accurately capture the movement of the moving object to calculate a motion vector or others for generating any new image signals. Thus generated image signals are expected to be high in precision because if any error is observed in the resulting image signals, image flickering will be caused.